Strength training, or weight training, has become tremendously popular within the past ten years. This is due primarily to the increased desire of people of all ages to stay fit by maintaining muscle tone, and the desire of some individuals within this group to also increase muscle bulk and/or strength.
Hammer Strength Corporation has succeeded in developing a line of innovative exercise machines which provide optimal muscular benefits during exercise by orienting the exercise motion along movement planes and/or arcs which most naturally accommodate the musculo-skeletal makeup of the human body. This success has been recognized by the U.S. Patent Office via issuance to this applicant of the following U.S. Pat. Nos.: D321,026; D321,027; D321028; D321,387; D321,389; D321,390; D321,391; 5,044,631; 5,044,632; 5,050,873; 5,066,003; 5,066,004; 5,106,080; 5,125,881; 5,135,449; 5,135,456; 5,171,198; 5,180,354; 5,181,896; 5,273,504; and 5,273,505. In addition to optimal muscular benefits, most of the commercial embodiments of these patented machines provide the "look and feel" of working out with free weights, but without the safety risks typically associated therewith.
Nevertheless, there still exists a need to improve upon the exercise mechanisms used to exercise certain muscle groups of the body, either because present mechanisms have proved ineffective for one reason or another or because safety issues have not been adequately addressed.
One such muscle group includes the calf muscles of the legs. The calf muscles are typically exercised by the exerciser by initiating a movement up on to the toes from a foot-horizontal position, thereby flexing the calf muscles. This initial movement is followed by lowering of the exerciser's heels back to a position horizontally even with the toes, thereby extending the calf muscles.
This calf exercise motion has been performed in the past on an exercise mechanism commonly referred to as a calf-raise machine. There are several different types of calf-raise exercise mechanisms. For each of these mechanisms, additional weight is added to the exerciser to make the calf flexion/extension movement more difficult, and better matched to the capabilities of the exerciser. For a calf-raise exercise mechanism referred to as a "donkey" calf raise, the additional weight that is exercised against is applied to the exerciser's hips, and the exerciser stands up but is bent forwardly during the exercise. For a calf-raise exercise mechanism referred to as an "erect" calf raise, the additional weight is applied to the exerciser's shoulders, and the exerciser stands straight up during the exercise. It has generally been thought that these mechanisms represent the best way to isolate the calf muscles during the calf flexion/extension motion for optimum muscular benefit.
However, with both of these mechanisms, the applied weight is placed not only on the exerciser's calves, but also on other parts of the body, such as the exerciser's lower back and hips. This extra weight applied to the lower back and hips of the exerciser and the entire back if performed from a standing position, helps the exerciser achieve optimum calf muscle exercise during the motion. However, this added weight places undue vertical compression upon the hips, the spinal column, or both. The added weight also compresses and bears directly against the body, via contact between the shoulders or
the hips with a relatively small pad. Because many exercisers require the use of a relatively large amount of weight to adequately work the calf muscles, i.e., in many instances up to 700 or 800 pounds, or even up to 1,000 pounds, the vertical compression applied to the hips and/or the spinal column during calf exercise motion is significant. Moreover, the compressive forces due to the weight bearing directly against the body are also significant.
As a result of these factors, the present mechanisms for exercising the calves restrict the access of exercisers who are recuperating from a back injury, exercisers who may be physically handicapped, some elderly exercisers, or other exercisers who for one reason or another cannot bear the application of these compressive and direct forces on the body. Even for healthy persons involved with weight training, over a long period of time the adverse effects of the compressive and the direct forces on the body will eventually take their physical toll.
Another type of calf-raise exercise is referred to as the bent leg calf-raise mechanism. With this mechanism, the exerciser sits straight up, with legs bent, and weight resistance to the calf raising motion is applied to the tops of the knees and the thighs of the exerciser. However, like the above-described machines, with this machine the additional weight is borne directly by the exerciser, on the knees and thighs. This may cause extreme discomfort for the exerciser during performance of the exercise. Also, compared to the donkey and erect calf raises, the seated bent knee calf raise does not provide the same range of calf flexion and extension, because the legs remain bent during performance.
Applicant is also aware of another prior art calf exercise mechanism which was at one time sold by Nautilus, but then discontinued. With this machine, the calf exercise was performed from a seated position, with legs extended horizontally, and the upper portions of the feet of the exerciser contacted and pivoted a lever about an axis centered on the ball-and-socket joints of the ankle. It is applicant's understanding that this machine was very uncomfortable, and that this discomfort led to the eventual discontinuance of the machine. Apparently, use of a rigid hinge axis through the ball-and-socket joint of the ankles does not simulate the normal, or natural, flexion/extension motion of the calf.
Also, with respect to prior art, some exercisers have used a seated leg press to perform calf exercise, by simply initially extending the legs and then performing calf extension and flexion. However, this can be dangerous. If the feet slip off the engagement plate, the weight causes the plate to move toward the exerciser at high speed, often slamming into the exerciser's knees. Due to this safety problem, these machines do not represent an acceptable solution.
It is an objective of this invention to improve upon present calf exercise machines by reducing the wear on the body caused by vertical compression on the spine and the other compressive and direct forces which result from the additional weight often used by the exerciser to effectively exercise the calf muscles via the calf flexion/extension motion.
It is another objective of this invention to increase the accessibility of calf exercise machines, to include exercisers within a wide range of ages and physical abilities, without sacrificing the muscular benefits associated therewith.
It is still another objective of this invention to optimize the muscular benefits attainable with a calf exercise machine, while at the same time enhancing safety, for a wide variety of exercisers.